The uplink-downlink configuration mode of Time Division Duplex (TDD for short) mode of the Long Term Evolution (LTE for short) system is as shown in table 1, wherein, D represents that the subframe is used for downlink transmission, U represents that the subframe is used for uplink transmission, S represents a special subframe and includes three special slots, i.e., a Downlink Pilot Time Slot (DwPTS for short, which is used for downlink transmission), a Guard Period (GP for short), and an Uplink Pilot Time Slot (UpPTS for short, which is used for uplink transmission). In the current actual system, the indexes of the uplink-downlink configuration will be notified to the terminal through a broadcast message.
TABLE 1Schematic table of uplink-downlink configurationConfig-Transition PointSubframe numbersurationsperiods01234567890 5 msDSUUUDSUUU1 5 msDSUUDDSUUD2 5 msDSUDDDSUDD310 msDSUUUDDDDD410 msDSUUDDDDDD510 msDSUDDDDDDD6 5 msDSUUUDSUUD
According to table 1, in the LTE-TDD system, when the TDD uplink-downlink configuration modes of different cells are the same, the uplink transmission implemented by the terminal of one cell is subjected to uplink interferences generated by uplink transmission implemented by the terminals of other cells, while when the TDD uplink-downlink configuration modes of different cells are different, the uplink transmission implemented by the terminal of one cell may be subjected to uplink interferences generated by uplink transmission implemented by the other uplink cell terminals, or may also be subjected to downlink interference generated by downlink transmission implemented by the other downlink cell base stations. Compared with the transmission power of the terminal, the transmission power of the base station is higher, and the downlink interferences generated by the downlink transmission implemented by the downlink cell base station is also relatively high, which will result in severe deterioration of the performance of the uplink transmission terminal, and even cause the terminal unable to implement communication.
At present, when the LTE terminal performs uplink transmission, the LTE terminal calculates the uplink transmission power according to the uplink open-loop power control parameter configured by the base station, and adjusts the uplink transmission power according to the uplink Transmit Power Control (TPC for short) command configured by the base station. Wherein, the base station transmits the uplink open-loop power control parameter to the terminal through Radio Resource Control (RRC) signaling; and the base station transmits the TPC command to the terminal through Downlink Control Information (DCI for short) in the Physical Downlink Control Channel (PDCCH for short), and the terminal acquires an adjustment value corresponding to the TPC command by decoding the DCI.
When uplink transmission is implemented in a certain cell and other base stations in a certain region surrounding the cell base station also implement uplink transmission, interferences to which the terminal in the cell is subjected when implementing uplink transmission is relatively small and varies a little, the adjustment of the uplink transmission power by the terminal according to the TPC command configured by the base station in accordance with the power adjustment mechanism in the related art can maintain the Signal to Interference and Noise Ratio (SINR for short) of the uplink transmission of the terminal at a certain level and satisfy the uplink transmission requirements thereof. When uplink transmission is implemented in a certain cell and other base stations in a certain region surrounding the cell base station implement downlink transmission, interferences to which the terminal in the cell is subjected when implementing uplink transmission becomes significantly large and also varies a lot. If the uplink transmission power continues to be adjusted by the terminal according to the TPC command configured by the base station in accordance with the power adjustment mechanism in the related art, it can not ensure SINR requirements of the uplink transmission thereof, thereby influencing the uplink transmission performance of the terminal and the system. That is, the use of the power adjustment mechanism in the related art by the terminal can not ensure that it adjusts the uplink transmission power on the uplink subframe to a relatively suitable power value, and thus can not ensure the uplink transmission performance of the terminal and the system.